/
AI Flashcards
Save to my account
Sign up
AI Flashcards
Nervous System Essentials
Study
1
Question
What is the anatomy and physiology of the nervous system? What are its main functions?
Page 1
Answer
The nervous system consists of the central nervous system (CNS: brain and spinal cord) and peripheral nervous system (PNS: nerves and ganglia). It detects stimuli, processes information, and coordinates responses via neurons and glial cells. Main functions include sensory input, integration, and motor output.
2
Question
What are neurons? Describe their structure.
Page 1
Answer
Neurons are excitable cells that transmit electrical and chemical signals. Structure includes a cell body (soma) with nucleus, dendrites (receive signals), axon (transmits signals), axon terminals (release neurotransmitters), and myelin sheath (insulates axon).
3
Question
What are synapses? Describe the types.
Page 1
Answer
Synapses are junctions between neurons or neuron and effector where signals pass. Types: chemical (neurotransmitter release across synaptic cleft) and electrical (direct ion flow through gap junctions).
4
Question
What are neurotransmitters? What are the main ones?
Page 1
Answer
Neurotransmitters are chemicals released by neurons to transmit signals across synapses. Main ones: acetylcholine (neuromuscular), glutamate (excitatory), GABA (inhibitory), dopamine (reward/movement), serotonin (mood), norepinephrine (arousal).
5
Question
Describe the organization of the nervous system.
Page 1
Answer
Organized into CNS (brain, spinal cord: integration) and PNS (sensory/afferent to CNS, motor/efferent from CNS). PNS divides into somatic (voluntary) and autonomic (involuntary: sympathetic/parasympathetic).
6
Question
What are reflexes? Describe the reflex arc.
Page 1
Answer
Reflexes are rapid, involuntary responses to stimuli. Reflex arc: sensory receptor → afferent neuron → integration center (CNS) → efferent neuron → effector (muscle/gland).
7
Question
What is the autonomic nervous system? Describe its divisions.
Page 1
Answer
Autonomic nervous system (ANS) regulates involuntary functions like heart rate, digestion. Divisions: sympathetic (fight-or-flight: norepinephrine, thoracolumbar outflow) and parasympathetic (rest-and-digest: acetylcholine, craniosacral outflow).
8
Question
Describe neurogenesis and neuronal plasticity.
Page 1
Answer
Neurogenesis is the formation of new neurons, mainly in embryonic stage but also in adult hippocampus. Neuronal plasticity is the ability of neural circuits to change structure/function in response to experience, including synaptic strengthening/weakening.
9
Question
What are glial cells? What are their functions?
Page 1
Answer
Glial cells support neurons. Functions: astrocytes (nutrient support, blood-brain barrier), oligodendrocytes/microglia (myelination, immune defense), ependymal cells (CSF production), Schwann cells (PNS myelination).
10
Question
Describe the blood-brain barrier.
Page 1
Answer
The blood-brain barrier (BBB) is a selective permeability barrier formed by endothelial cells of brain capillaries, astrocytes, and pericytes, protecting the brain from toxins while allowing nutrients like glucose.
11
Question
What is the action potential? Describe its generation.
Page 1
Answer
Action potential is a rapid change in membrane potential: depolarization (Na+ influx via voltage-gated channels), repolarization (K+ efflux), hyperpolarization. Generated when threshold (~-55 mV) reached from graded potentials.
12
Question
Describe the propagation of the nerve impulse.
Page 1
Answer
Nerve impulse (action potential) propagates along axon via local currents depolarizing adjacent membrane, regenerating the AP. Saltatory conduction in myelinated axons jumps between nodes of Ranvier for speed.
13
Question
What are graded potentials? How do they differ from action potential?
Page 1
Answer
Graded potentials are local changes in membrane potential varying in strength, decremental, from stimuli. Differ from action potential: graded are subthreshold, non-propagating; AP all-or-nothing, regenerating.
14
Question
Describe chemical and electrical synapses.
Page 1
Answer
Chemical synapses: presynaptic neuron releases neurotransmitters into synaptic cleft, binding postsynaptic receptors to open ion channels. Electrical synapses: gap junctions allow direct ion flow between cells for rapid synchronization.
15
Question
What is spatial and temporal summation in synapses?
Page 1
Answer
Spatial summation: multiple synapses activate simultaneously to reach threshold. Temporal summation: repeated activation of one synapse in quick succession sums to threshold.
16
Question
Describe the main neurotransmitters and their functions.
Page 1
Answer
Acetylcholine: muscle contraction, memory. Glutamate: excitatory learning. GABA: inhibitory anxiety control. Dopamine: reward, movement. Serotonin: mood, sleep. Norepinephrine: alertness, stress response.
17
Question
What is neuromodulation?
Page 1
Answer
Neuromodulation is the alteration of neurotransmitter release or postsynaptic receptor sensitivity by neuromodulators (e.g., neuropeptides like endorphins), fine-tuning synaptic transmission over longer periods.
18
Question
What are ganglia? Describe their function in the nervous system.
Page 2
Answer
Ganglia are clusters of neuron cell bodies outside the CNS. Function: relay and integrate signals in PNS, e.g., autonomic ganglia for sympathetic/parasympathetic relays, sensory ganglia for dorsal root.
19
Question
Describe ascending and descending nerve pathways.
Page 2
Answer
Ascending pathways: carry sensory info from periphery to CNS (e.g., spinothalamic for pain). Descending pathways: carry motor commands from CNS to effectors (e.g., corticospinal for voluntary movement).
20
Question
What is sensory information? Describe its processing.
Page 2
Answer
Sensory information is stimuli detected by receptors (e.g., light, touch). Processing: transduction to electrical signals, transmission via afferents to CNS, integration in brain for perception.
21
Question
What are sensory receptors? Classify them.
Page 2
Answer
Sensory receptors convert stimuli to nerve impulses. Classification: mechanoreceptors (touch, pressure), thermoreceptors (temperature), photoreceptors (light), chemoreceptors (chemicals), nociceptors (pain).
22
Question
Describe sensory transduction.
Page 2
Answer
Sensory transduction is the conversion of stimulus energy (e.g., light, sound) into receptor membrane potential changes (graded potentials), leading to action potentials in sensory neurons.
23
Question
What is sensory adaptation?
Page 2
Answer
Sensory adaptation is the decrease in receptor response and sensation intensity despite constant stimulus, e.g., ignoring clothes on skin, allowing focus on changing stimuli.
24
Question
Describe the somatosensory system.
Page 2
Answer
Somatosensory system processes touch, pressure, pain, temperature, proprioception from body. Pathways: dorsal column (fine touch/vibration) to medulla → thalamus → somatosensory cortex.
25
Question
What are nociceptors? Describe their function.
Page 2
Answer
Nociceptors are sensory receptors detecting painful stimuli (mechanical, thermal, chemical). Function: transmit pain signals via A-delta (sharp/fast) and C fibers (dull/slow) to CNS for protective withdrawal.
26
Question
Describe pain perception.
Page 2
Answer
Pain perception involves nociceptor activation, transmission via spinothalamic tract to thalamus and cortex, modulated by gate control (e.g., rubbing eases itch) and endogenous opioids.
27
Question
What is proprioception?
Page 2
Answer
Proprioception is the sense of body position and movement, mediated by receptors in muscles, tendons, joints, detecting stretch and tension for coordination without vision.
28
Question
Describe proprioceptive receptors.
Page 2
Answer
Proprioceptive receptors: muscle spindles (detect muscle length/stretch), Golgi tendon organs (detect tension), joint receptors (position). Send info via afferents to cerebellum and cortex.
29
Question
What are Golgi tendon organs?
Page 2
Answer
Golgi tendon organs are sensory receptors in tendons detecting muscle tension during contraction, inhibiting excessive force via autogenic inhibition to prevent injury.
30
Question
Describe the stretch reflex.
Page 2
Answer
Stretch reflex is monosynaptic reflex maintaining muscle tone: muscle spindle detects stretch → Ia afferent to spinal cord → alpha motor neuron → muscle contraction.